Actuating mechanism for fluid displacement and pressurizing device

ABSTRACT

A fluid displacement device, particularly for use of the device to pressurize balloon catheters, or the like. The device includes a plunger which is displaceable through a housing, and an actuating mechanism which engages the plunger. The actuating mechanism includes a nut member that is biased into engagement with a threaded portion of the plunger. The device has a press-to-release feature wherein the plunger is instantly releaseable by simply depressing a control surface to overcome a restorative spring force. Subsequently, the plunger can be translated using macro movements (i.e., by pushing or pulling the plunger).

RELATED APPLICATIONS (PRIORITY CLAIM)

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/341,678, filed on Dec. 22, 2008, which claims the benefit ofU.S. Provisional Application Ser. No. 61/114,192, filed Nov. 13, 2008.The above-noted applications are hereby incorporated herein by referencein their entirety.

BACKGROUND

This invention relates to fluid pressurizing devices for ballooncatheters or the like, and more particularly relates to an improveddevice for actuating a screw plunger and monitoring the resulting fluidpressurization.

Fluid pressurization devices adapted for selectively applying andrelieving a measured pressure on a closed volume of fluid have beendeveloped for use in inflation and deflation of a balloon catheter usedin angioplasty balloon procedures interiorly of blood vessels, or othertypes of balloon catheterization procedures. For example, U.S. Pat. No.4,838,864 discloses a syringe device which inflates and deflates acatheterized balloon. The device uses a manually-operated screw plungerto achieve or maintain specific balloon pressure, and the pressure ismonitored using an associated pressure gauge. Improved syringing andpressurization control is also described in U.S. Pat. Nos. 5,168,757;5,713,242; and 6,796,959, all three of which are owned by the assigneeof the present invention and are hereby incorporated herein in theirentirety by reference. These patents disclose quick release mechanismswhich enable rapid advancement of a plunger and alternatively allowthreaded engagement with the screw plunger to achieve precise controlduring final pressurization of a balloon catheter.

A cross-sectional view of the device which is disclosed in U.S. Pat. No.5,796,959 is shown generally in FIG. 1 herein (FIG. 1 herein correspondsto FIG. 4 of the '959 patent). As shown, the device 40 provides that apiston 48 is engaged with a plunger 68 inside a fluid displacementchamber 44 that is provided in a cylindrical syringe body or housing 42.A pressure gauge assembly 58 is threadably engaged with the housing 42,and the end 64 of the housing 42 is configured for engagement with ahose 54, such as a hose that is connected to a balloon catheterstructure. The piston 48 has a sealing member 50 thereon which sealswith an internal wall 72 of the housing 42. The plunger 68 can beretracted to pull fluid through the hose 54 into the device 40, and canbe extended (or pushed in) to push fluid out of the device 40 and intothe hose 54.

The plunger 68 can also be locked in place to prevent being pushed orpulled (i.e., to prevent macro movement of the plunger 68).Specifically, the device 40 includes a nut member 80 which can be movedinto and out of engagement with a threaded portion 86 of the plunger 68.When the nut member 80 is not engaged with the threaded portion 86 ofthe plunger 68, as shown in FIG. 2, the plunger 68 can be extended orretracted (i.e., pushed or pulled) using macro movements. In contrast,when the nut member 80 is engaged with the threaded portion 86 of theplunger 68, as shown in FIG. 3, the plunger 68 is locked in placeagainst macro movements, and can only be translated by using micromovements (i.e., by turning a knob 74 of the plunger 68).

To facilitate movement of the nut member 80, there are two link members102, 104 which are engaged with the nut member 80 and which are retainedon the device 40 by a pivot pin 106. The link members 102, 104 arepositioned and configured to operate in tandem. As shown in FIGS. 2 and3, the nut member 80 also includes a lever or grip portion 96 which canmanipulated in order to shift the nut member 80, causing the nut member80 to move into and out of engagement with the threaded portion 86 ofthe plunger 68. In order to move the nut member 80 into or out ofengagement with the threaded portion 86 of the plunger 68, the linkmembers 102, 104 must clear past ribs 120 (see FIGS. 2 and 3) which areprovided on flanges 83 (see FIG. 1) which extend from the housing 42.Because the amount of force which is required to cause the link members102, 104 to move past the ribs 120 depends on a plurality of partdimensions and tolerances, maintaining uniform detenting forces from oneunit to the next, and from product line to product line, has provenchallenging.

Another difficulty that can occur from time to time involves userconvenience. Some users have found difficultly in reaching and engagingthe lever 96 of the nut member 80 due to a combination of themanipulation required to perform the action and the operator's handlocations during certain procedures with the device 40, such as when theplunger 68 has been fully extended for vacuum and has to be locked intoplace. In such instances, the operator's hands can end up too far fromthe lever 96 to operate it without changing grip. During adisengage-withdraw plunger-reengage manipulation sequence (as occurswhile drawing vacuum to pull down an interventional balloon afteroperation at pressure), users are forced to traverse the ribs 120 on thehousing 42 twice by going one way and then back again the otherdirection in order to reengage the threaded plunger and hold it in awithdrawn position. Having to traverse the ribs 120 twice also occurswhen manipulating to go from full vacuum or zero pressure torepressurization of the balloon.

Another disadvantage of the device 40 shown in the '959 patent relatesto assembly. As shown in FIGS. 8-11 of the '959 patent, assemblyrequires alignment and sliding of the first link member 102 into the nutmember 80, followed by upside down insertion of the second link member104 into the nut member 80, and then 180 degree rotation of the secondlink 104 to align it with the first one 102. This requires manipulationand assembly time. Additionally, due to the need for free andindependent rotation of the two link members 102, 104, it is notpossible to be certain that these link members 102, 104 always stay inalignment with one another or are properly located in the nut member 80to receive the pivot pin 106 during assembly.

Furthermore, precise longitudinal alignment is not generally possiblewith regard to the two link members 102, 104 and the nut member 80, andto both the pivot pin 106 and the threads 86 on the plunger 68.Specifically, each link member 102, 104 is free to pivot out ofalignment slightly with the other and consequently allow the nut member80 to slightly twist or deflect out of alignment with the plunger's axisduring engagement and disengagement manipulations. Such twist ispossible even though plunger 68 and pivot pin 106 are maintained instrict parallel alignment to one another. This undesirable deflectionoffers potential for a deleterious effect upon mating thread componentsresulting in uneven loading and occasional chipping of the most highlyloaded threads during disengagement during maximum pressure useconditions.

OBJECTS AND SUMMARY

An object of an embodiment of the present invention is to provide animproved fluid displacement device.

Another object of an embodiment of the present invention is to providean improved process for assembling a fluid displacement device.

Still another object of an embodiment of the present invention is toprovide a fluid displacement device which is relatively easy toassemble.

Briefly, and in accordance with at least one of the foregoing objects,an embodiment of the present invention provides a fluid displacementdevice, particularly for use of the device to pressurize anddepressurize catheters, or inject fluid, or aspirate fluid, or the like.The device includes a plunger which is displaceable through a housing,and an actuating mechanism which engages the plunger. The actuatingmechanism includes a nut member and a unitary link member that providesan integral spring. The integral spring of the unitary link memberprovides that the nut member is biased into engagement with the threadedportion of the plunger. As such, the plunger is normally in the “locked”position, thereby preventing macro movements (i.e., pushing or pulling)of the plunger but allowing micro movements (i.e., turning) of theplunger. The actuating mechanism is configured to provide apress-to-release feature wherein the plunger is instantly releaseable bysimply depressing a control surface, such as a control surface on thenut member or unitary link member, to overcome a restorative springforce provided by the integral spring of the unitary link member.Subsequently, the plunger can be translated using macro movements (i.e.,by pushing or pulling the plunger).

Another aspect of the present invention provides a method of assemblinga fluid displacement device. The assembly method includes assembling anactuating mechanism of the device by engaging a unitary link member witha nut member, whereby integral spring force of the unitary link membertends to hold the unitary link member in place on the nut member. A pinis then engaged with the unitary link member and the nut member, therebyforming an assembly. This assembly is then inserted in an opening in thehousing and another pin is used to retain the assembly on the device.

The structure and method of assembling the fluid displacement deviceprovide several advantages, as will be described more fully laterhereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The organization and manner of the structure and operation of theinvention, together with further objects and advantages thereof, maybest be understood by reference to the following description, taken inconnection with the accompanying drawings, wherein like referencenumerals identify like elements in which:

FIG. 1 is a cross-sectional view of a prior art fluid displacementdevice, specifically that which is disclosed in U.S. Pat. No. 6,796,959;

FIGS. 2 and 3 are enlarged views which illustrate two differentpositions of an actuating mechanism of the fluid displacement devicewhich is shown in FIG. 1;

FIG. 4 is a perspective view of a fluid displacement device which is inaccordance with an embodiment of the present invention;

FIG. 5 is a cross-sectional view of the fluid displacement device shownin FIG. 4;

FIG. 6 is an exploded perspective view of the fluid displacement deviceshown in FIGS. 4 and 5;

FIG. 7 is an enlarged exploded perspective view of a portion of thefluid displacement device shown in FIGS. 4-6, specifically an actuatingmechanism thereof;

FIG. 8 is a partial cross-sectional view of the fluid displacementdevice shown in FIGS. 4-6, showing the actuating mechanism biased intoengagement with a plunger of the device;

FIG. 9 is a partial cross-sectional view of the fluid displacementdevice shown in FIGS. 4-6, showing the actuating mechanism beingactuated such that it has moved out of engagement with the plunger;

FIG. 10 is a front, elevational view of a carrier member component ofthe fluid displacement device shown in FIGS. 4-6;

FIG. 11 is a rear, elevational view of the carrier member;

FIG. 12 is a top, plan view of the carrier member;

FIG. 13 is a side, elevational view of the right side of the carriermember;

FIG. 14 is a side, elevational view of the left side of the carriermember;

FIG. 15 is a cross-sectional view of the carrier member, taken alongline 15-15 of FIG. 11;

FIG. 16 is a cross-sectional view of the carrier member, taken alongline 16-16 of FIG. 11;

FIG. 17 is a cross-sectional view of the carrier member, taken alongline 17-17 of FIG. 14;

FIG. 18 is a partial cross-sectional view of the actuating mechanism ofthe fluid displacement device shown in FIGS. 4-6, showing an internalrib feature;

FIG. 19 is a perspective view of a fluid displacement device which is inaccordance with another embodiment of the present invention;

FIG. 20 is an exploded perspective view of the fluid displacement deviceshown in FIG. 19;

FIG. 21 is an enlarged exploded perspective view of a portion of thefluid displacement device shown in FIGS. 19-20, specifically anactuating mechanism thereof;

FIG. 22 is a partial cross-sectional view of the fluid displacementdevice shown in FIGS. 19-20, showing the actuating mechanism biased intoengagement with a plunger of the device;

FIG. 23 is a partial cross-sectional view of the fluid displacementdevice shown in FIGS. 19-20, showing the actuating mechanism beingactuated such that it has moved out of engagement with the plunger; and

FIG. 24 is an enlarged exploded perspective view of alternativeactuating mechanism.

DESCRIPTION

While the invention may be susceptible to embodiment in different forms,there are shown in the drawings, and herein will be described in detail,specific embodiments with the understanding that the present disclosureis to be considered an exemplification of the principles of theinvention, and is not intended to limit the invention to that asillustrated and described herein.

One specific embodiment of the present invention is shown in FIGS. 4-6while another specific embodiment is shown in FIGS. 19 and 20. Stillanother variation of these two is shown in FIG. 24. The embodiment shownin FIGS. 4-6 will be described first, and then differences between thatembodiment and the other variations will be discussed.

A first, specific embodiment of the present invention comprises a fluiddisplacement device 200 (see FIGS. 4-6) which utilizes all the samecomponents of the device disclosed in U.S. Pat. No. 5,796,959, exceptfor replacing the nut member 80 and link members 102, 104 of the '959device with a unitary link 202, a nut member 204, and a pivot pin 206.As such, U.S. Pat. No. 5,796,959 is hereby incorporated herein byreference in its entirety.

As shown in FIGS. 4-6, the fluid displacement device 200 which is inaccordance with a specific embodiment of the present invention has agenerally cylindrical syringe body or housing 208 which provides a fluiddisplacement chamber 210 (see specifically FIG. 5). Preferably, thehousing 208 is transparent thereby facilitating the viewing of fluid inthe fluid displacement chamber 210 during fluid aspiration ordispensing. The housing 208 is formed of plastic, and may be molded frompolycarbonate or another type of resin. The housing 208 has volumetricindicia thereon, such as at location 212 indicated in FIG. 4, so that aphysician can readily determine the volume of fluid contained in thechamber 210. As shown, handles 214 are provided on the housing 208 tofacilitate gripping of the device 200 and operation thereof.

A piston 216 is slidably displaceable within the fluid displacementchamber 210 (i.e. in the housing 208). A sealing member 218, such as aquad ring, is disposed on the piston 216. As shown in FIG. 5, preferablythe sealing member 218 is disposed between two walls 220 on the piston216. As will be described more fully later hereinbelow, a lubricant maybe used to place the sealing member 218 on the piston 216. The sealingmember 218 is configured for pressure retention and the prevention ofleakage of fluid past the piston 216 in the fluid displacement chamber210. The housing 208 includes a fluid conduit 222 which is incommunication with the fluid displacement chamber 210. The fluid conduit222 is also in communication with a hose 224 that is connected to, forexample, balloon catheter structure (not shown), a fluid supplyreservoir (not shown) or some other suitable structure depending on theapplication. As shown in FIG. 6, a connector 226 may be provided on thehose 224, between the fluid conduit 222 and the balloon catheter.

As shown in FIG. 5, the fluid conduit 222 also communicates with apressure gauge assembly 228. Preferably, the pressure gauge assembly 228is engaged directly with the housing 208, such as threadably engagedwith a threaded bore 230 (see FIGS. 5 and 6) thereon. To this end, thepressure gauge assembly 228 is provided with a threaded portion 232which threadably engages the threaded bore 230 on the housing 208. Anadhesive may be provided between the threaded portion 232 and thethreaded bore 230 to lockingly and sealingly engage the parts together.As shown in FIGS. 5 and 6, the threaded bore 230 is provided generallyproximate an end 234 of the housing 208 such that, when installed, thepressure gauge assembly 228 is disposed generally proximate a distal endof the device. The pressure gauge assembly 228 is configured to providea physician with an indication of the pressure in the fluid conduit 222and balloon catheter. The pressure gauge assembly 228 can be of anysuitable type for either angioplasty or for other employment of thedevice 200. The fact that the device 200 is configured such that thepressure gauge assembly 228 engages directly with the housing 208provides increased visibility proximate the distal end of the device.Such visibility becomes important when a physician is to purge all theair bubbles from the fluid displacement chamber 210 before using thedevice 200 to dispense fluid. Alternatively, the device 200 can beconfigured such that the pressure gauge assembly 228 engages a clampingcover such as is shown and described in U.S. Pat. No. 5,713,242, whichhas been incorporated herein by reference in its entirety.

As best shown in FIG. 5, the piston 216 is mounted on an unthreadedpilot nose end 236 of a plunger 238. The pilot nose end 236 isconfigured to freely rotate in a central journal cavity 240 of thepiston 216. The piston 216 is mounted on the pilot nose end 236 of aplunger 238 in a snap-action, interference coupling which prevents thepilot nose end 236 from withdrawing or backing out of the centraljournal cavity 240 of the piston 216 when the plunger 238 is retractedto aspirate fluid into the fluid displacement chamber 210. The pilotnose end 236 is freely rotatable relative to the coupled piston 216. Assuch, when the plunger 238 is rotated (i.e., during micro movements),the piston 216 does not rotate along with the plunger 238, but generallyadvances or retracts linearly in the housing 208. As shown in FIGS. 4-6,the plunger 238 preferably includes an integral palm knob 244 whichfacilitates movement of the plunger 238 as will be described in moredetail hereinbelow.

The device includes an actuating mechanism 246 which is normally biasedinto engagement with the plunger 238, but which can be actuated out ofengagement with the plunger 238. When the actuating mechanism 246 (seeFIG. 7) is biased into engagement with the plunger 238, macro movementsof the plunger 238 are not generally possible, only micro movements are.When macro movements are prevented, the plunger 238 cannot be pushedinto or pulled out of the housing 208 (i.e., to displace a large amountof fluid quickly). Instead, the plunger 238 can only be translated byrotating its knob 244 (i.e., to displace fluid slowly, with moreprecision). On the other hand, when the actuating mechanism 246 isactuated out of engagement with the plunger 238, macro movements of theplunger 238 are possible. When macro movements are possible, the plunger238 can be pushed into or pulled out of the housing 208.

As shown in, for example, FIG. 7, the actuating mechanism 246 comprisesa unitary link 202, a nut member 204, and a pivot pin 206. The pivot pin206 extends through holes 248 on the nut member 204 and though apassageway 250 in the unitary link 202, thereby effectively retainingthe unitary link 202 on the mating nut member 204 and forming anassembly. As shown in FIGS. 7 and 18, the pivot pin 206 is preferablyprovided with a reduced diameter middle portion 252 which receives acentral rib 254 within the unitary link 202 which locks the pivot pin206 in place relative to the unitary link 202. Specifically, the pin 206has a cruciform shape, with lower cruciform members 255 being providedbetween two central disk features 256. These lower cruciform members 255effectively form a groove 258 on the pivot pin 206, wherein the raisedrib 254 in the unitary link 202 is configured to catch in the groove 258on the pivot pin 206 and hold the pivot pin 206 in place.

As shown in FIGS. 4 and 5, the overall assembly is disposed in thehousing 208, generally near a rearward end 260 of the housing 208.Specifically, as shown in FIGS. 4-6, the actuating mechanism 246 ispreferably disposed in an aperture 262 in the housing 208, where theaperture 262 is provided between a pair of spaced flanges 264, and theactuating mechanism 246 is mounted on the device 200 viz-a-viz a pin266, which is preferably made of metal,

As viewed in FIGS. 5-7, the nut member 204 has threads 268 which areformed in a lower base portion 270, and the nut member 204 includes anupstanding, bifurcated portion which provides a pair of spaced, elongatearm or mounting portions 272 (see specifically FIG. 7). The mountingportions 272 in effect define carriage structure, and are generallyintegral with the threads 268. Each of the mounting portions 272 has anaperture 274 therein, through which the plunger 238 extends (seespecifically FIGS. 5, 8 and 9), as well as a hole 248 for receiving thepivot pin 206.

FIG. 8 illustrates how it is that the nut member 204 is biased intoengagement with the plunger 238. Specifically, a spring finger portion276 of the unitary link 202 engages an external surface 278 of the nutmember 204, and this contact along with the rigidity of the springfinger portion 276 of the unitary link 202 generates a restorativespring force which tends to keep the nut member 204 in the positionshown in FIG. 8, wherein the threads 268 on the nut member 204 areengaged with threads 279 of the plunger 238. In this position, theplunger 238 cannot be pushed into or pulled out of the housing 208 usingmacro movements. Instead, the plunger 238 must be translated using onlymicro movements, i.e. by turning its knob 244, causing the threads 279of the plunger 238 to worm along the threads 268 of the nut member 204.As described above, the pilot nose end 236 of the plunger 238 isconfigured to freely rotate in the central journal cavity 240 of thepiston 216. Hence, rotation of the plunger 238 while the threads 268 ofthe nut member 204 are engaged with the threaded portion 279 of theplunger 238 generally does not cause the piston 216 to rotate in thefluid displacement chamber 210 in the housing 208, but instead allowsthe piston 216 to merely slide in the housing 208.

To provide the integral spring feature (i.e., the spring finger 276) ofthe unitary link 202, the unitary link 202 is made of a material thathas both excellent compressive strength and good stiffness coupled witha high degree of elasticity to allow deflection without plasticdeformation or breakage. Acetal resin, commercially known as Delrin orCelcon for instance, offers these properties, but to a lesser degreethan do Nylon, Polypropylene or similar elastic materials. Acetel isoften preferred for polymer spring applications due to its ability towithstand large degrees of deflection without plastic deformation orfracture along with its inherent lubricity, hardness and resistance toenvironmental stress, cracking and wear. In the application disclosedherein, the part must be able to tolerate pivoting and sliding againstmating components of Nylon and metal for which Acetal is known toperform particularly well.

By virtue of the return spring force being sufficient to keep the device200 in a plunger-engaged, default position, ribs (identified withreference numeral 120 in FIGS. 2 and 3, herein) such as is shown in U.S.Pat. Nos. 5,713,242 and 6,796,959, and the additional user effort whichis required to overcome them, are no longer necessary. When the nutmember 204 is biased into engagement with the plunger 238 as shown inFIG. 8, the nut member 204 is in an “over-center” locking position whichensures that any slight motion of the nut member 204 which could beinduced by fluid pressure in the fluid displacement chamber 210 imposedon piston 216 results in tighter engagement of the plunger 238 and nutmember 204 rather than any tendency for loosening or disengagementthereof.

The nut member 204, and specifically the threads 268 thereof, isselectively disengageable from the plunger 238 in order to permit manualrapid displacement of the plunger 238 and piston 216, for example, foraspiration of saline solution into the fluid displacement chamber 210from a fluid supply reservoir (not shown) which may be connected to thehose 224 or in which connector 226 may be immersed. The disengagement ofthe nut member 204 from the plunger 238 also enables rapid advancementof the plunger 238 and piston 216, for example, to discharge solutionthrough the hose 224 to inflate an angiolplasty balloon (not shown)which has been previously positioned within a blood vessel or heartvalve using a balloon catheter. Rapid retraction of the plunger 238 andpiston 216 may also enable swift aspiration of fluid into the fluiddisplacement chamber 210 for rapid deflation of an angiolplasty balloon.Also, prior to connection to the catheter, the plunger 238 may beoperated to insure that all air bubbles have been eliminated from thefluid which is contained in the fluid displacement chamber 210.

In order to facilitate the selective disengagement of the threads 268 ofthe nut member 204 with the threaded portion 279 of the plunger 238, asshown in FIG. 9, the nut member 204 is provided as having a controlsurface such as a lever 280 (see FIGS. 4, 8 and 9), whereindisengagement of the nut member 204 is achieved by pressing down on thelever 280 (as represented by arrow 282 in FIG. 9). Pressing down on thelever 280, as shown in FIG. 9, causes the assembly to traverse, andcauses the spring finger portion 276 of the unitary link 202 to ridealong the external surface 278 of the nut member 204 and be deflectedoutwardly. Displacement of the nut member 204 is preferably guided alonga translating motion between the positions shown in FIGS. 8 and 9. Themotion of the nut member 204 in moving between the positions of FIGS. 8and 9 is in actuality that of a diminishing curved path and, as such, isnot truly linear. When the lever 280 of the nut member 204 is presseddown, the spring finger portion 276 of the unitary link 202 becomesflexed, generally creating a bias of the assembly back into the positionshown in FIG. 8. As such, releasing the lever 280 causes the assembly toreturn to the position shown in FIG. 8. FIG. 8 illustrates the normal,non-actuated position of the nut member 204 in which the threads 268 ofthe nut member 204 are biased into engagement with the threaded portion279 of the plunger 238, thereby locking the plunger 238 with regard tomacro movements. However, micro movements of the plunger 238 arepossible by rotating its knob 244, causing the threads of the plunger238 to worm along the threads 268 on the nut member 204.

In contrast, FIG. 9 illustrates what occurs when a user presses down onthe lever 280 of the nut member 204. As shown, this causes the nutmember 204 to traverse, causing the threads 268 of the nut member 204 tobecome disengaged from the threaded portion 279 of the plunger 238. Insuch a position, the plunger 238 may be axially translated in the fluiddisplacement chamber 210 by pushing the plunger 238 forward into thehousing 208, or by pulling the plunger 238 back out of the housing 208.In other words, pushing or pulling the plunger 238 is prevented when thenut member 204 is engaged with the plunger 238. However, pushing thelever 280 of the nut member 204 down causes the nut member 204 todisengage the plunger 238, thereby allowing the plunger 238 to be pushedor pulled.

Although only optional, the nut member 204 preferably includes a camfeature 284 as shown in FIGS. 6-9. When the lever 280 of the nut member204 is pushed down, the spring finger 276 of the unitary link 202 mustride up on the cam 284, as shown in FIG. 9. The cam 284 works toincrease the closing force (i.e., the tendency for the overall actuatingmechanism 246 to return to the position shown in FIG. 8) and provide adefinitive location to assure that the at-rest position (see FIG. 8,wherein the lever 280 of the nut member 204 is not being pressed) isfully achieved by the nut member 204 rather than allowing this positionto be indeterminate as may be the case without the cam feature. The camfeature 284 provides both auditory and tactile feedback to the user withregard to whether the nut member 204 is engaged with the plunger 238. Toprovide more definitive feedback, the cam feature 284 may be configuredto provide a sharp step for spring finger 276 to ride over andsubsequently return over. This provides that the spring finger 276 willsnap over cam 284, providing more definitive auditory and tactilefeedback to the user of the released or engaged position of threads 268with plunger 238.

As shown in FIGS. 5, 6, 8 and 9, preferably the device 200 includes acarrier member 290 that is received in the housing 208, much like thedevice shown in U.S. Pat. 6,796,959. As shown in FIGS. 6 and 10-17, thecarrier member 290 may be provided in the form of a generally hollow,generally cylindrical part. The carrier member 290, like the housing208, may be formed of plastic. In fact, the carrier member 290 and thehousing 208 may be formed of the same resin.

As shown in FIGS. 5, 6, 10, 11, 15 and 17, the carrier member 290 hasspaced-apart walls 298, 300, and the walls 298, 300 are provided withapertures 294 through which the plunger 238 extends, as well asapertures 296 which retain the pin 266 that secures the actuatingmechanism 246 to the device 200. More specifically, the carrier member290 supports the pin 266, and the pin 266 extends through a bore 275 inthe unitary link 202, thereby providing that the pin 266 generallyretains the actuating mechanism 246 on the device 200.

As shown in FIG. 6, wall 298 defines the front surface of the carriermember 290 (see also FIG. 10, which provides a view of the front of thecarrier member 290), and wall 300 defines the rear surface of thecarrier member 290 (see also FIG. 11, which provides a view of the rearof the carrier member 290). A partial wall 302 extends between the frontand rear walls 298 and 300 of the carrier member 290. A cut out 304 isdefined between the walls 298 and 300, and the nut member 204 isdisposed in the cut out 304 (see FIG. 5). The pin 266 extends throughthe apertures 296 provided in the carrier member 290, and the carriermember 290 generally retains the pin 266 such that the pin 266 does notreadily move axially. As shown in FIG. 6, the pin 266 may be providedwith a knurled end portion 306 which assists in preventing the pin 266from translating axially once it is installed in the carrier member 290.

As shown in FIGS. 6 and 10-15, protruding surfaces 308 are provided onan external surface 310 of the carrier member 290, generally proximatethe rear end of the carrier member 290. Corresponding inward facingflanges 312 are provided in the housing 208, at the rearward end 206thereof, for receiving interruptions between protruding surfaces 308provided on the carrier member 290. Preferably, the flanges 312 in thehousing 208 and the interruptions between protruding surfaces 308 on thecarrier member 290 provide that the carrier member 290 can be insertedin a bore 314 in the end 260 of the housing 208, and then rotated tosecure the carrier member 290 in the housing 208. Specifically, thecarrier member 290 and housing 208 are configured such that the carriermember 290 is installable through the rear portion of the housing 208 inthe bore 314 in the housing 208 via a quarter-turn bayonet arrangement,wherein the carrier member 290 is axially inserted in the bore 314 andthen given a one-quarter turn to lock the carrier member 290 in place.

The carrier member 290 includes a latching finger 316 which is formed aspart of the partial wall 302 which extends between the front and rearwalls 298, 300 of the carrier member 290. The latching finger 316preferably engages an inwardly extending rib 318 provided on an internalwall of the housing 208 (see FIG. 6). Specifically, the latching finger316 engages and clears the inwardly extending rib 318 on the housing 208in a manner which generally locks the carrier member 290 in place in thebore 314 in the housing 208. Preferably, the latching finger 316 andinwardly extending rib 318 are configured such that an audible noise isproduced as the latching finger 316 engages and clears the inwardlyextending rib 318. The noise is loud enough to provide an audibleindication to an assembler of the device 200 that the carrier member 290is fully installed in the bore 314.

Preferably, another inwardly extending rib 320 is provided on theinternal wall of the housing 208 exactly opposite rib 318 (i.e. 180degrees from rib 318, along the interior wall of the housing 208). Aprotruding surface 322 is provided on the external surface 310 of thecarrier member 290, generally extending from protrusion 308 of thecarrier member 290 toward the front end of the carrier member 290. Whenthe carrier member 290 is inserted in the bore 314, the protrudingsurfaces 308 abut the proximal ends of ribs 318 and 320 (see FIGS. 5 and8-10) of the housing 208 to prevent the carrier member 290 frominstalling too far axially into the bore 314. In other words, engagementof the protruding surfaces 308 with ribs 318 and 320 limits axial travelof the carrier member 290 in the bore 314 during installation. Once theprotruding surface 308 contacts ribs 318 and 320, the carrier member 290is rotated such that it becomes fully installed. Preferably, not onlydoes the latching finger 316 of the carrier member 290 engage and clearthe inwardly extending flange 318 on the housing 208, but the protrudingsurface 308 on the carrier member 290 engages behind the oppositeinwardly extending flanges 312 on the internal surface of the housing208. When the carrier member 290 is fully installed in the bore 314, thecarrier member 290 cannot be readily axially withdrawn from the bore314, nor can the carrier member 290 be readily rotated in eitherrotational direction relative to the housing 208. When the carriermember 290 is properly installed in the housing 208, the cut out 304 inthe carrier member 290 is generally aligned with the aperture 262 in thehousing 208.

The nut member 204, unitary link 202 and pin 206 (i.e., the actuatingmechanism 246) is received in the cut out 304 in the carrier member 290and the aperture 262 in the housing 208 such that the lever 280 of thenut member 204 generally extends out the aperture 262 in the housing 208for easy access, as shown in FIGS. 4, 8 and 9. The carrier member 290 issecurably engaged relative to the housing 208, and the pin 266 whichsecures the actuating mechanism 246 is retained by the carrier member290.

The carrier member 290 is configured to withstand in-use forces as theplunger 238 is translated forward in the fluid displacement chamber 210.The carrier member 290 permits the device 200 to be assembled from therear of housing 208 (i.e. is rear loaded), as will be described morefully later hereinbelow in connection with describing assembly of thedevice. Additionally, as shown in FIG. 5, the carrier member 290provides that a distance from a center line of the plunger 238 to aninternal wall 242 of the housing 208 can be greater than a distance fromthe center line of the plunger 238 to the pin 266.

Still further, the design of the device 200, by including the carriermember 290, provides that many of the parts are universal such that theyare compatible with devices of different sizes.

Specifically, the nut member 204 and plunger 238 may be used inassociation with different sized devices, specifically devices withdifferent sized fluid displacement chambers. The carrier member 290shown in the Figures is designed to be used with fluid displacementchambers which are as large as that shown in the Figures or which aresmaller than that shown in the Figures. Of course, a larger or smallersized device can be provided than is depicted in the Figures, which arenot to scale.

Despite all the advantages that are provided by having the deviceinclude the carrier member 290, the device can instead be provided asnot having a carrier member, such as is disclosed in U.S. Pat. No.5,713,242, which has been incorporated herein by reference.

Regardless, the device 200 is configured such that a user need notchange grip of the device 200 during use. The lever 280 of the nutmember 204 just needs to be pressed to effect plunger 238 disengagement,and ribs (identified with reference numeral 120 in FIGS. 2 and 3) neednot be overcome to move back and forth between a plunger-engaged and aplunger-disengaged position. Additionally, release of the lever 280provides instant plunger 238 re-engagement. By virtue of the returnspring force provided by the spring finger 276 of the unitary link 202being sufficient to keep the device 200 in a plunger-engaged defaultstate (as shown in FIG. 8), detents or ribs on the housing 208 andadditional user effort required to overcome them are no longernecessary.

A method of assembling the device 200 will now be described, in thesituation where the device does, in fact, include a carrier member 290such as disclosed in U.S. Pat. No. 6,976,959. To assemble the device200, hose 224 may be affixed to the housing 208. Then, the pressuregauge assembly 228 is threadably engaged with the housing 208.Subsequently, the sealing member 218 is fit onto the piston 216. Tofacilitate this, a lubricant can be used as illustrated by applicator332 shown in FIG. 6. Then, the piston 216 is slipped into bore 314 inthe housing 208 (i.e. from right-to-left in FIG. 5). In other words, thepiston 216 is rear loaded into the device 200. Then, the carrier member290 is installed on the housing 208, also from the rear portion of thehousing 208. As described above, this installation may be via aquarter-turn bayonet style installation wherein the carrier member 290is axially inserted into the bore 314 and then is rotated a quarter-turnto lock the carrier member 290 in place relative to the housing 208. Asdescribed above, preferably the locking finger 316 on the carrier member290 emits a snapping or clicking sound once the carrier member 290 isfully and properly installed. When the carrier member 290 is properlyinstalled in the housing 208, the cut out 304 in the carrier member 290is generally aligned with the aperture 262 in the housing 208.Subsequently, the actuating mechanism 246 can be installed in theaperture 262. However, before the actuating mechanism 246 is installed,the actuating mechanism 246 must be assembled.

To assemble the actuating mechanism 246, the unitary link 202 is clippedonto the nut member 204, and the pivot pin 206 is used to secure theunitary link 202 to the nut member 204. Even before the pivot pin 206 isused to secure the unitary link 202 to the nut member 204, the unitarylink 202 tends to stay in place relative to the nut member 204 due tothe spring force provided by the integral spring feature 276 of theunitary link 202. To secure the unitary link 202 to the nut member 204,the pivot pin 206 is pushed through one hole 248 on the nut member 204,though a passageway 250 in the unitary link 202, and into the other hole248 in the nut member 204, thereby effectively forming an assembly. Asshown in FIG. 18, when the pivot pin 206 is in place, a central rib 254in the unitary link 202 engages a reduced diameter middle portion 252 ofthe pivot pin 206, thereby locking the pivot pin 206 in place relativeto the unitary link 202. Once the actuating mechanism 246 is assembled,the actuating mechanism 246 can be inserted into the aperture 262, andthe pin 266 used to secure the actuating mechanism 246.

After the actuating mechanism 246 has been installed on the device 200,the lever 280 of the actuating mechanism 246 is pushed down, and theplunger 238 is axially inserted into the rear end 260 of the housing 208into engagement with the piston 216. Specifically, the nose end 236 ofthe plunger 238 is inserted through bore 314, through the bore 274provided in the nut member 204, and into snap-fit engagement with thepiston 216 within the fluid displacement chamber 210. Thereafter, thelever 280 of the actuating mechanism 246 can be released, and device 200is thereafter operable.

As described hereinabove, assuming the device is provided in accordancewith U.S. Pat. No. 6,976,959, and includes a rear-loading carriagemember 290, the device is configured to be assembled from the rear.Specifically, both the piston 216 and carrier member 290 are installedin the rear of the housing 208. By providing that the device isassembled from the rear, the housing 208 can be provided as a single,integral piece. The front portion of the housing 208 can be molded aspart of the housing 208, and no extra fittings or clamping covers needto be used to mount the gauge 228 to the housing 208. The gauge 228 canbe engaged directly with the housing 208. Hence, the design has fewerparts and requires less labor than if the device were provided as beingconsistent with that which is shown in U.S. Pat. No. 5,713,242.Additionally, there is no issue with regard to sealing the front of thedevice 200 because the front portion of the device 200 is integral withthe remainder of the housing 208. Moreover, visibility at the front ofthe device 200 is improved, and this is advantageous to a user who isattempting to prime the device 200 before use by purging all the airbubbles from the chamber 210. By providing that the housing 208 ismolded as a single piece, the housing 208 can be manufactured in asingle molding operation, thereby reducing the cost of the componentsand the molds, creating less waste and streamlining the production andassembly process.

Furthermore, the design of the device 200, by including the carriermember 290, provides that many of the parts are universal such that theyare compatible with devices of different sizes. For example, the carriermember 290 shown in the FIGURES is designed to be used with fluiddisplacement chamber 210 s which are as large as that shown in theFIGURES or which are smaller than that shown in the FIGURES.

Notwithstanding the fact that using a carrier member 290 providesseveral advantages, using a carrier member 290 is not imperative toemploying the present invention. As discussed above, the presentinvention can be used in association with, for example, the devicedisclosed in U.S. Pat. No. 5,713,242, which does not include a carriagemember.

Benefits derived from the actuating mechanism 246 disclosed hereininclude elimination of a pair of links, such as disclosed in U.S. Pat.Nos. 5,713,242 and 6,796,959, in exchange for a single unitary link 202that, by virtue of its integrated spring form, is designed to beself-fixturing through its ability to be clipped precisely in positionto the mating nut member 204 and thereby retain itself perfectly forreceiving insertion of the pivot pin 206 as well as the pin 266 whichsecures the actuating mechanism 246 to the device 200. With the designsdescribed in U.S. Pat. Nos. 5,713,242 and 6,796,959, assembly requiredalignment and sliding of a first link into its receiving bore followedby up-side-down insertion of a second link onto its receiving bore, thensubsequent 180 degree rotation of the second link to align it with thefirst one. Much more manipulation and thereby assembly time wasinvolved. By comparison, assembly of the actuating mechanism 246disclosed herein simply involves clipping the unitary link 202 onto thenut member 204, where it retains itself by virtue of its integral leafspring element 276, and then inserting the pivot pin 206 through boththe nut member 204 and the unitary link 202 to hold the assemblytogether. As discussed above, the pivot pin 206 is preferably made witha reduced diameter middle portion 252 which receives a central rib 254that is provided in the unitary link 202, which locks the pin 206 inplace. This stable, locked together sub-assembly eases subsequentassembly of the inflation device because there are no loose or floppyparts requiring further alignment before the pin 266 is used to mountthe actuating mechanism 246 on the device 200. Additionally, the unitarylink 202 becomes automatically positioned to receive the pins 206 and266. In contrast, with the devices disclosed in U.S. Pat. Nos. 5,713,242and 6,796,959, due to the need for free and independent rotation of thepair of links within their respective bores, it was not possible to becertain that these links always stayed in alignment with one another orproperly located within the nut member to receive a pin duringsubsequent assembly of the inflation device. The finished devicemanufacturer also realizes a distinct advantage through elimination ofthe detenting mechanism (i.e., the ribs) because obtaining consistentdetent resistance is difficult due to detent interference levels beingthe product of difficult-to-control tolerance variations from threeindependent parts that become interdependent when assembled.

A significant additional benefit of providing a unitary link 202 inplace of a pair of links is the ability of the unitary link 202 tomaintain a more precise longitudinal alignment of the nut member 204 toboth the pivot pin 206 and the mating threads 279 on the plunger 238.Precise longitudinal alignment was not previously possible with twoseparate links since each link was free to pivot out of alignmentslightly with the other and consequently allow the nut member toslightly twist or deflect out of alignment with the plunger's axisduring engagement and disengagement manipulations. Such twist waspossible even though plunger and the pin were maintained in strictparallel alignment to one another. This undesirable deflection offerspotential for a deleterious effect upon mating tread componentsresulting in uneven loading and occasional chipping of the mosthighly-loaded threads during disengagement during maximum pressure useconditions. A unitary link 202 offers far less potential for twisting ordeflection compared to two independent links and thereby yields a morerobust mechanism.

Another benefit of the actuating mechanism 246 disclosed herein is thedesign's self-contained nature, its independence from having to reactagainst any additional external structure to obtain thrust necessary tourge the nut member 204 into constant engagement with the plunger 238.Instead, engagement results from thrust of the unitary link's springelement 276 constantly pulling the nut member 204 toward the pin 206 inorder to reach a relaxed unstressed condition. This self-containedaction simplifies the overall device design and allows the unitary link202 to co-exist on the assembly line with the earlier, paired linkmechanism in order to allow phasing in of the newer design while theolder one remains in production. Medical devices are highly regulatedand even minor changes must be properly evaluated and validated by eachcustomer before they can be accepted. Due to need for extensivevalidation work by each and every customer and changes to printed userinstructions, wholesale changeover to a new mechanism is not possibleand there will be a period of time where both constructions must bemanufactured at the same time as customers switch over, one by one. Nothaving to change the larger device structure that houses this mechanismreduces overall tooling expense, eliminates processing changes and makesprocess and component revalidations unnecessary for the device housing208 structure thereby simplifying and speeding market introduction ofthe new design.

As discussed above, FIGS. 4-6 illustrate a fluid displacement device 200which is in accordance with a specific embodiment of the presentinvention, and that device 200 has been described in detail hereinabove.FIGS. 19-20 illustrate a fluid displacement device 200 a which is inaccordance with an alternative embodiment of the present invention. Thisalternative embodiment has many of the same parts. As such, identicalreferences numbers are used, and a detailed discussion of those parts isgoing to be omitted when discussing the embodiment shown in FIGS. 19-20.

The only difference between the two embodiments (i.e., fluiddisplacement device 200 and fluid displacement device 200 a) is thatinstead of providing a control surface in the form of a lever 280 on anut member 204, the control surface of the fluid displacement device 200a is provided in the form of a lever 280 a on a unitary link 202 a. Assuch, the only difference between the fluid displacement device 200shown in FIG. 4-6 and the fluid displacement device 200 a shown in FIGS.19-20 is that the unitary link 202 a and the nut member 204 a of theqfluid displacement device 200 a are shaped differently than the unitarylink 202 and the nut member 204 of the fluid displacement device 200.The preferred shape and configuration of the unitary link 202 a and thenut member 204 a are shown in FIGS. 19-20, and FIG. 21 illustrates theactuating mechanism 246 a that is provided by the unitary link 202 a,the nut member 204 a, and the pivot pin 206.

In operation, the fluid displacement device 200 a shown in FIGS. 19-20works effectively the same as the fluid displacement device 200 shown inFIGS. 4-6 and previously described, except that instead of pressing on acontrol surface in the form of a lever 280 on a nut member 204 to togglethe device (as is performed in associate with fluid displacement device200), fluid displacement device 200 a provides that one presses on acontrol surface in the form of a lever 280 a on the unitary link 202 ain order to toggle the device. While FIG. 22 shows the nut member 204 abiased into engagement with the plunger 238, FIG. 23 shows the nutmember 204 a moved out of engagement with the plunger 238.

It is more preferable to provide the control surface on the unitary link(as is provided in association with the fluid displacement device 200 a)than to provide the control surface on the nut member (as is provided inassociation with the fluid displacement device 200) because itsimpliufies the design and therefore the tooling of the nut member foreasier manufacture of the nut member while having minimal impact uponthe design and ease of manufacture of the unitary link.

FIG. 24 illustrates an alternative actuating mechanism 246 b that can beemployed instead of either one of the actuating mechanisms 246, 246 apreviously described, preferably in association with a fluiddisplacement device having all the same parts as fluid displacementdevice 200 or 200 a. Like the actuating mechanisms 246, 246 a previouslydescribed, the actuating mechanism 246 b shown in FIG. 24 includes a nutmember 204 b and a pivot pin 206. While the nut member 204 b is exactlythe same as nut member 204 a, the unitary link 204 b is different fromunitary link 204 a. Specifically, instead of providing a control surfacein the form of a lever 280 a as is provided on unitary link 202 a, theunitary link 202 b shown in FIG. 24 provides a control surface in theform of a surface of the unitary link 202 b.

In operation, a fluid displacement device which employs the actuatingmechanism 246 b shown in FIG. 24 works much the same way as the fluiddisplacement devices 200, 200 a previously described, except thatinstead of pressing on a control surface in the form of a lever 280 on anut member 204 or a lever 280 a on a unitary link 202 a, the controlsurface 280 b is pressed to actuate the device.

While specific embodiments of the present invention are shown anddescribed, it is envisioned that those skilled in the art may devisevarious modifications of the present invention without departing fromthe spirit and scope of the foregoing disclosure.

The invention claimed is:
 1. A toggle locking mechanism for a fluiddisplacement device which has a housing and a plunger which extends intothe housing, said toggle locking mechanism having a link memberconfigured to provide a biasing force to pull the mechanism into aself-locked condition by drawing a locking member tightly against thelink member that provides the biasing force, wherein the link member hasa control surface which is pressable to cause the nut member todisengage the plunger.
 2. A toggle locking mechanism as recited in claim1, wherein the locking member comprises a nut member having threadswhich are biased into engagement with threads on a plunger, but which isselectively disengageable with the threads on the plunger.
 3. A togglelocking mechanism as recited in claim 1, wherein a pivot pin secures thelink to the locking member.
 4. A toggle locking mechanism as recited inclaim 3, wherein a rib on the link engages and secures the pivot pinrelative to the link.
 5. A toggle locking mechanism as recited in claim1, wherein the locking member comprises a cam surface, wherein the linkhas a spring finger which rides up the earn surface of the lockingmember when the control surface of the link member is pressed.
 6. Atoggle locking mechanism as recited in claim 5, wherein the cam surfaceis configured to provide at least one of auditory and tactile feedbackregarding whether the locking member is engaged with the plunger.
 7. Anactuating mechanism on a fluid displacement device which has a housingand a plunger Which extends into the housing, said actuating mechanismcomprising a nut member which is biased into engagement with theplunger, but which is selectively disengageable with the plunger,further comprising a link member which has a control surface which ispressable to cause the nut member to disengage the plunger.
 8. Anactuating mechanism as recited in claim 7, wherein the nut membercomprises threads which engage corresponding threads on the plunger. 9.An actuating mechanism as recited in claim 7, wherein the link member ison the nut member, further comprising a pivot pin which secures the linkmember to the nut member.
 10. An actuating mechanism as recited in claim9, wherein the link member has a spring finger which contacts anexternal surface of the nut member.
 11. An actuating mechanism asrecited in claim 10, wherein the spring finger is configured to providethat the nut member is biased into engagement with the plunger.
 12. Anactuating mechanism as recited in claim 10, wherein the spring fingercontacts a cam surface on the nut member and provides at least one ofauditory and tactile feedback regarding whether the nut member isengaged with the plunger.
 13. A method of assembling a fluiddisplacement device which has a plunger, said method comprising:assembling an actuating mechanism by securing a unitary link to a nutmember; securing the actuating mechanism to the fluid displacementdevice; actuating the actuating mechanism; sticking the plunger throughthe actuating mechanism; and de-actuating the actuating mechanism,wherein the nut member engages the plunger, and wherein the unitary linkhas a control surface which is pressable to cause the nut member todisengage the plunger.
 14. A method as recited in claim 13, wherein thestep of assembling the actuating mechanism comprises engaging a unitarylink with a nut member, wherein the unitary link tends to stay engagedwith the nut member due to a spring finger portion of the unitary linkcontacting an external surface of the nut member, and using a pivot pinto secure the unitary link to the nut member.
 15. A method as recited inclaim 14, wherein the step of using the pivot pin to secure the unitarylink to the nut member comprises having a rib on the unitary link engageand secure the pivot pin relative to the unitary link.
 16. A method asrecited in claim 14, wherein the step of securing the actuatingmechanism to the fluid displacement device comprises using a pin tosecure the actuating mechanism.
 17. A method as recited in claim 14,wherein the step of actuating the actuating mechanism comprises pressinga control surface of a link, thereby causing the nut member to traverserelative to the unitary link.
 18. A method as recited in claim 17,wherein the step of de-actuating the actuating mechanism comprisesreleasing the control surface of a link member, thereby causing the nutmember to move into engagement with the plunger.